Means for retaining magazine-fed firearm cartridges in bolt pickup position



IN VEN TOR EdmnndIRn'lei h E. J. RALEIGH MEANS FOR RETAININGMAGAZINE-FED FIREARM CARTRIDGES IN BOLT PICKUP POSITION Filed Jan. 15,1961 Wa -ma W Sept. 18, 1962 United States Patent Ofllice 3,054,206Patented Sept. 18, 1962 Secretary of the Army Filed Jan. 13, 1961, Ser.No. 82,660 4 Claims. (Cl. 42-18) (Granted under Title 35, US. Code(1952), see. 266) The invention described herein may be manufactured andused by or for the Government for governmental purposes without thepayment of any royalty thereon.

This invention relates to magazine fed firearms with reciprocating boltsand more particularly to devices for supporting the top cartridges in amagazine so as to assure positive pickup by the bolt and to buflerdevices for resiliently stopping the bolt in the recoil position thereofand energizing the bolt for counterrecoil flight.

With those firearms which fire at a rapid rate and have a reciprocatingbolt which transfers a cartridge from a magazine to the barrel chamberwhen traveling from the recoil to the battery position, a nonfiringcondition oftentimes develops through the leading cartridge in themagazine being below the path of travel of the bolt when passingthereby. This condition is caused by the surge produced in the magazinespring, as it functions to move the cartridges in the magazine upwardlytherein when the leading cartridges are successively removed by thebolt, and the rapid rate of fire which does not permit time for thesurging to subside in the spring between the cyclic functions thereof.

It is, therefore, an object of this invention to provide a retainerdevice which supports the leading cartridge in a magazine to assurepickup by the bolt.

It is another object of this invention to provide such a retainer devicewhich is actuated by the bolt.

It is a further object of this invention to provide such a retainerdevice which also serves as a buffer for the bolt.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawing in which:

FIG. 1 is a longitudinally cross-sectioned view of a firearm receivershowing the bolt disposed between the battery and recoil positionthereof and the leading cartridge in the magazine engaged with theunderside of the retainer;

FIG. 2 is a fragmentary view similar to FIG. 1 but showing the boltstopped in the recoil position by the buffer-retainer and the leadingcartridge in the magazine released by the retainer for displacement tothe position for pickup by the bolt;

FIG. 3 is a view similar to FIG. 2 but showing the buffer-retainerforwardly displaced to extend the forward end thereof into engagementwith the pickup position cartridge for support thereof and the boltenergized for counterrecoil flight;

FIG. 4 is a view taken along line 4'4 of FIG. 3; and

FIG. 5 is an enlarged view of the butter-retainer.

Shown in the figures is a firearm receiver 12 in which a cylindricalbolt 14 is slidingly received by a channel 16 for longitudinalreciprocation in recoil and counterrecoil strokes to and from a recoilposition. Receiver 12 is provided with a vertically disposed well 18which extends therethrough to channel 16 and which is adapted to receivea cartridge magazine 20. Magazine 20 is of double-stacked type wherein aplurality of stored cartridges 22 are moved alternately and in contactrelationship from the two stacks to a central neck 24 for successiveremoval by bolt 14 during the counterrecoil strokes thereof. Theremaining cartridges 22 in magazine 20 are forced by a spring 26 thereintowards neck 24 as the leading cartridge therein is removed by bolt 14.

Provided in receiver 12 is a chamber section 32 of rectangularcross-section, which extends rearwardly into receiver 12 from the rearend of well 18 and which is open at the top to channel 16. Chambersection 32 is terminated at the rear end by a wall 34 which extendsvertically upward to channel 16. A bore 36 extends longitudinallyrearward from wall 34 to a bottom 37 and receives a compressible coilspring 38 for contact therewith.

A buffer-retainer 40 includes a cylindrical shaft 42, which is slidinglyreceived by bore 36 forwardly of spring 38, and an integral plate 44laterally disposed on the front end of the shaft. Plate 44 has arectangular cross-section of approximately the same dimensions as thoseof chamber section 32 so that the plate is slidingly received thereby.The top of plate 44 extends upwardly into channel 16 and is providedwith an arcuate, mating relief 45 for bolt 14.

The free end of shaft 42 contacts the front end of spring 3% to biasbuffer-retainer 4t} forwardly. The forward displacement ofbuffer-retainer 44) is limited by the contact of a stop 46 extendingradially from shaft 42 with the front end of a slot 48 extendingupwardly from bore 36 to channel 16. The rearward displacement ofbuffer-retainer 413 is limited by the contact of plate 44 with wall 34.

Extending forwardly from plate 44 is a pair of laterally spaced tines5'0 which, when buffer-retainer 40 is rearwardly displaced, areretracted within chamber section 32. When buffer-retainer 4-0 isforwardly displaced, tines 5d extend through an opening 51 in the rearside of magazine 2i) for engagement with the underside of the base ofcartridge 22 in neck 24. Tines 50 are spaced apart a distance slightlyless than the diameter of the base of cartridge 22 and are verticallypositioned so as to be insertable into the clearances on opposite sidesof the area of contact between the leading cartridge in neck 24 and thenext succeeding cartridge when the leading cartridge is positioned forpickup by bolt 14. By tines 5% being so spaced apart the succeedingcartridge 22 in magazine 24 is displaceable a portion of the pitch ofmovement of the cartridges in neck 24 when the leading cartridge isremoved therefrom. Whereby, such succeeding cartridge 22, now theleading cartridge, has to be displaced only slightly more than ahalf-pitch when released, as hereinafter described, by butterretainer 40to the position in neck 24 for pickup by bolt 14.

Provided on the front portion of each of the tines 50 is a spiral ramp52 which extends rearwardly and upwardly from the front end thereof.Ramps 52 assure the engagement of the base of the leading cartridge 22in neck 24 by tines 50 when buffer-retainer 40 is forwardly displaced.Tines 50 are disposed so that, when extended under the base of theleading cartridge 22, the base is raised so as to project upwardly intothe path of bolt 14 to assure engagement thereby during displacementfrom the recoil position.

Buffer-retainer 40 is actuated rearwardly, against the bias of spring38, by the contact of a radial flange 56 on bolt 14 with the front sideof plate 44 during the recoil strokes of bolt 14. Flange 56 is disposedadjacent the front end of bolt 14 so that tines 50 extend forwardlytherebcyond when the flange and plate '44 are in contact. The contact offlange 56 with plate 44 during recoil travel of bolt 14, which displacesbufler-retainer 4t) rearwardly against the bias of spring 38, releasescartridge 22 engaged with the underside of tines 50. When released, suchcartridge 22 is moved under the bias of spring 26 into pickup positionin neck 24. Moreover,

3 through the engagement of buffer-retainer 40 by bolt 14, the energytherein is partially absorbed by spring 38, before being stopped inrecoil position by the contact of plate 44 with wall 34, to provide abuffer for the bolt. The stored energy in spring 38 energizes bolt 14for the succeeding counterrecoil stroke thereof.

Thus, when bolt 14 is in battery, the rear end of the leading cartridge22 in magazine 20 is in engagement with the undersides of tines 50 so asto project radially upward therebetween but so as to be clear of flange56, as shown in FIG. 1, when the bolt travels in recoil responsive todischarge forces. \Vhen bolt 14- is adjacent recoil position during therecoil stroke thereof, flange 56 contacts plate 44 to provide a bufferfor the bolt and retract tines 50 within chamber section 32 for releaseof the engaged cartridge 22.

The released cartridge 22 is immediately biased upwardly into pickupposition in neck 24 and the contact of plate 44 with wall 34 stops bolt14 in the recoil position thereof. Spring 26 must have sufficientresiliency and the reciprocation of bulfer-retainer 40 with bolt 14-must be suflicient to assure that the released cartridge 22 will reachpickup position in neck 24 by the time that the front end of tines 50are positioned, during counterrecoil of the bolt, for engagement withthe underside of such cartridge. The ramps 52 on the front ends of tines50 assure extension thereof beneath the leading cartridge 22. Therefore,the leading cartridge 22 is positively positioned by tines 50 so that,when stop 46 contacts the front end of slot 48 to stop the forwarddisplacement of buffer-retainer 4t and bolt 14 continues incounterrecoil relative thereto, the base of such cartridge is isolatedby tines t? from the influence of spring 26 and supported for positivecontact by the front end of the bolt. When the leading cartridge 22 inmagazine 20 is transferred therefrom by bolt 14, the succeedingcartridge in the magazine is pressed upwardly by spring 26 intoengagement with the undersides of tines 50.

From the foregoing it is clearly apparent that there is provided hereina device which serves the dual purpose of retaining a cartridge in amagazine in position for positive contact by a reciprocating bolt and ofbuflflng the recoil strokes thereof, which buffer-retainer device issimple and rugged in construction and positive in its functions.

Although a particular embodiment of the invention has been described indetail herein, it is evident that many variations may be devised withinthe spirit and scope thereof and the following claims are intended toinclude such variations.

I claim:

1. In a firearm, the combination including a receiver, a bolt disposedin the receiver for longitudinal reciprocation to and from a recoilposition, a magazine arranged for moving cartridges successively from astored supply therein to a neck of said magazine and in position forpickup by said bolt during displacement thereof from the recoilposition, and a device disposed in the receiver so as to be engageablewith the pickup position cartridges for retention thereof in positionfor pickup by said bolt and so as to resiliently stop said bolt in therecoil position and energize said bolt for flight therefrom.

2. In a firearm, the combination including a receiver, a bolt disposedin the receiver so as to be energized for longitudinal reciprocation toand from a recoil position, a magazine arranged for moving cartridgestherein successively and in contact relationship to a neck of saidmagazine in position for pickup by said bolt during displacement thereoffrom the recoil position, a bulfer-retainer device mounted forlongitudinal reciprocation in the receiver adjacent said magazine, saidbuffer device including retainer means engageable with the pickupposition cartridges for retention thereof in position for pickup by saidbolt during displacement from the recoil position and spring meansdisposed for biasing said retainer means into engagement with the pickupposition cartridges, and a flange disposed on said bolt for engagementwith said buffer-retainer device during displacement of said bolt to therecoil position for actuating said retainer means so as to bedisplaceable into engagement with the pickup position cartridges and fortransferring recoil energy from said bolt to said spring means toresiliently stop said bolt at the recoil position and energize said boltfor flight therefrom.

3. The combination as defined in claim 2 wherein said retainer meansincludes a pair of tines laterally disposed so as to be engageable withthe pickup position cartridges on opposite sides of an area of contactof the pickup position cartridge with a succeeding cartridge in saidmagazine and so as to permit limited radial displacement of thesucceeding cartridge therebetween when the pickup position cartridge isremoved from said magazine by said bolt.

4. The combination as defined in claim 2 wherein the receiver isprovided with a vertical well for receiving said magazine, a chambersection extending rearwardly from the top of said well to a verticallydisposed wall and a bore extending longitudinally rearward therefrom;wherein said buffer-retainer device includes a shaft slidingly disposedin said bore, an integral plate laterally disposed on the front end ofsaid shaft so as to be slidingly received by said chamber section and becontactable with said wall to stop rearward displacement of saidbuifer-retainer device and means for stopping the forward displacementthereof to limit the longitudinal reciprocation of said buffer-retainerdevice; wherein said retaining means includes a pair of tines extendingintegrally forward from said plate so that when the forward displacementof said buffer-retainer is stopped by said stopping means said tinesextend into said magazine for engagement with the pickup positioncartridge to support the cartridge for contact by said bolt duringdisplacement from the recoil position and so that when said plate is incontact with said wall said tines are retracted from said magazine intosaid chamber section; wherein said spring means is disposed in said borerearwardly of said shaft for biasing said buffer-retainer deviceforwardly; and wherein said flange is integrally disposed on said boltadjacent the front end thereof so that when said flange and said plateare in contact said tines extend forwardly beyond said bolt to engagethe pickup position cartridge before contact thereof by said bolt duringflight thereof from the recoil position.

